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【 Q & A 】
问题:
当客户或竞争者提到"电容器可连续过电压1.1倍,因此在400V的电网中,若
加装6% 电抗器后,电容器仅需选用440V即可,不需使用480V级电容器耐压,
因为440V可耐过电压达484V "
分析:
1. 首先我们要对"IEC-60831"的电容器过电压的规定,有所了解













其明确指出:在电力频率下(Power frequency)系统电压调整(reg ulation)
及浮动下(fluctuations),电容器可连续过电压1.1倍
我们称此为"系统变动电压"

然而加装电抗器时电容器需考虑的电压为:电抗器的压升及谐波所造成的
压升,此种电压我们称为"固定压升"

因此电容器制造时就必须符合标准,对"系统变动电压"就必须考虑;然而
加装电抗器时必须考虑"固定压升"这样才能使电容器无过电压的危险.

TypeVoltage factor
×Un(r.m.s)Observation
Maximun
duration
Power
Frequency
Power
frequency
Power
frequency
Power
frequency
Power
Frequency
Power
frequency
plus hormonic
Highest average value during any period
of capacitorenergization. For energization
periods less than 24hexceptions apply as
indicated below (Clause 29)
System voltage regulationand fluctuations
System voltageregulationand fluctuations
Voltage rise at light load(Clause 29)
Continuous
8 h in
every 24h
30 min in
every 24h
5 min
1 min
1.00
1.10
1.15
1.20
1.30
Such that the current does not exceed the value given in Clause 21
(see also Clause 33 and Clause 34)
IEC60831